1. FIELD OF THE INVENTION
The present invention relates to a silver halide photographic light-sensitive element having a dyed hydrophilic colloid layer.
2. DESCRIPTION OF THE PRIOR ART
In a silver halide photographic light-sensitive element, a photographic emulsion layer or another hydrophilic colloid layer is often dyed for the purpose of absorbing light having a specific wavelength range.
When the spectral composition of the light introduced into a photographic emulsion layer must be controlled, a dyed layer is usually provided at a position farther away from the support than the photographic emulsion layer. Such a dyed layer is designated a filter layer. In the case of a multilayer color light-sensitive element having a plurality of photographic emulsion layers, the filter layer layer can be positioned between photographic emulsion layers.
In order to prevent image blurring, namely, halation caused by the fact that light scattered on passing through the photographic emulsion layer or after transmission is reflected at an interface between the emulsion layer and the support or a surface of the light-sensitive element opposite the emulsion layer and is introduced again into the photographic emulsion layer, a dyed layer is usually provided between the photographic emulsion layer and the support or on the surface of the support opposite the photographic emulsion layer. Such a dyed layer is designated an antihalation layer. In the case of a plurality of photographic emulsion layers such as exists in a multilayer color light-sensitive element, the antihalation layer can be positioned between photographic emulsion layers.
In order to prevent a deterioration of the sharpness of images due to scattering of light in a photographic emulsion layer (this phenomenon is called irradiation), the photographic emulsion layer can also be dyed.
Generally, a water soluble dye is added to the hydrophilic colloid layer to be dyed. The dye used for such a purpose should not only have an appropriate spectral absorption according to the purpose of use but also the following properties.
1. The dye should be photographically chemically inactive. Namely, the dye should not have an adverse chemical influence upon the properties of the silver halide photographic emulsion layers, for example, reduction of sensitivity, deterioration of latent images or fog, etc. PA1 2. The dye should be decolored during photographic processings or the dye should dissolve in the processing solutions or water used for rinsing and should not result in a coloration of the photographic light-sensitive element after processing.
In order to discover dyes which satisfy these requirements, much effort has been expended by persons skilled in the art. For example, oxonol dyes having a pyrazolone nucleus represented by the dyes described in British Pat. No. 506,385, oxonol dyes having a barbituric acid nucleus represented by the dyes described in U.S. Pat. No. 3,247,127, oxonol dyes described in U.S. Pat. Nos. 2,533,472 and 3,379,533 and British Pat. No. 1,278,621, hemioxonol dyes represented by the dyes described in British Pat. No. 584,609, styryl dyes represented by the dyes described in U.S. Pat. No. 2,298,733, merocyanine dyes represented by the dyes described in U.S. Pat. No. 2,493,747 and cyanine dyes represented by the dyes described in U.S. Pat. No. 2,843,486 are known.
Many of the dyes which are decolored during processing of the photographic emulsion can be decolored by sulfites (or bisulfites) included in processing solutions or by sulfites under alkaline conditions, for example, as described in British Pat. No. 506,385.
Where the dyed layer is a filter layer or where the dyed layer is an antihalation layer positioned on the support and on the same side of the support as the photographic emulsion layer(s), such a layer often must be selectively dyed while other layers should not substantially be affected. If such a requirement is not satisfied, the dye not only produces a harmful spectral effect upon other layers but also the dye deteriorates effects as a filter layer or as an antihalation layer.
In order to selectively dye a specified hydrophilic colloid layer, many processes are known. However, a process which comprises incorporating a hydrophilic polymer having a charge of the opposite polarity to a dye ion as a mordanting agent in the hydrophilic colloid layer, whereby the dye is present in the specified layer due to a mutual interaction between the dye molecule and the hydrophilic polymer, is most commonly used (it is believed that not only an attraction due to the charges but also a hydrophobic bond contributes thereto).
As the mordanting agent, there can be exemplified polymers derived from ethylenically unsaturated compounds having a dialkylaminoalkyl ester group as described in British Pat. No. 685,475, reaction products prepared by reacting a polyvinylalkylketone with aminoguanidine as described in British Pat. No. 850,281 and polymers derived from 2-methyl-1-vinyl-imidazole as described in U.S. Pat. No. 3,445,231. Where a process involving mordanting by such polymers is used, if the layer containing the dye is contacted with another hydrophilic colloid layer in the wet state, a portion of the dye often diffuses from the dye layer to the other colloid layer. Such a diffusion of the dye depends not only on the chemical structure of the mordanting agent but also on the chemical structure of the dye used.
Where the above described high molecular weight mordanting agent is used, residual color in the light-sensitive element easily results after photographic processings and particularly after photographic processings where the processing time is shortened. The reason therefor is believed to be that the dye or a reversible decolored product remains in the layer containing the mordanting agent because some bonding strength of the dye to the mordanting agent remains, even though the bonding strength becomes considerably weakened in alkaline solutions such as a developer solution. Although such difficulty depends on the chemical structure of the mordanting agent to a great extent, it also depends on the chemical structure of the dye.
Of the various water soluble dyes used for dyeing the hydrophilic colloid layer of a photographic light-sensitive element, merocyanine dyes having a benzoxazole nucleus as described in U.S. Pat. Nos. 3,148,187 and 3,282,699 have been preferred because they are irreversibly decolored in a developer solution containing sulfites and hardly have any adverse influence on the photographic properties of the photographic emulsion. However, the above described merocyanine dyes are sufficiently mordanted only by a specific basic polymer and often diffuse from the layer containing a basic polymer to other layers, even though acid groups such as sulfo groups are introduced into both terminals of their molecules.